Jack



Mardl 1965 w. H. POWERS ETAL 3,175,352

JACK

Filed Nov. 17, 1961 2 Sheets-Sheet l NVENTORS.

. Powers.

air/V19 March 30, 1 w. H. POWERS ETAL 3,175,362

JACK Filed Nov. 17, 1961 2 Sheets-Sheet 2 l I s /1 INVENTORS.

4 "4% Uzi-M iyw United States Patent 3,175,362 JAQK Walter H. Powers and Lyle L. Arnes, both of Racine, Wis, assignors to Walker Manufacturing Company, Racine, Win, a corporation of Delaware Filed Nov. 17, 1961, Ser. No. 153,175 9 Claims. ((31. 60-51) This invention relates to jacking apparatus, and more particularly to lifting jacks of the type adapted for use with automotive vehicles as well as for other applications.

In conventional lifting jacks, such as are presently used for raising automobiles, the energy expended in lifting the load is translated into potential energy but the latter is lost when the load is lowered and is tran formed into useless frictional energy or heat. It is an object of the present invention to provide a lifting jack which will be capable of harnessing some of the potential energy when the load is lowered and storing it for use the next time the jack is used to raise a load.

It is also an object to provide an improved jack of this character which is especially adapted for lifting springsupported loads, and which may find particular application as a bumper jack for automotive vehicles.

It is another object to provide an improved lifting jack of this nature which is extremely simple in construction, is safe to use, and requires little maintenance.

It is a further object to provide an improved jack having the above characteristics, which is versatile in operation and is capable of being extended to different lengths depending on the desired movement of the load.

Other objects, features, and advantages of the present invention will become apparent from the subsequent description, taken in conjunction with the accompanying drawings.

In the drawings:

FIGURE 1 is an end elevational view of a jack constructed according to the principles of the invention, showing the energy storage compartments as well as the main jack body;

FIG. 2 is a side elevational view, partially in cross section, taken along the line 2-2 of FIGURE 1 and showing the energy storage valve;

FIG. 3 is a fragmentary cross-sectional view in elevation taken along the line 33 of FIGURE 1 and showing the pump and its associated structure; and

FIGS. 4 and 5 are diagrammatic views of a portion of an automobile body and wheel, showing the manner in which the novel jack may be used as an aid in lifting spring-supported loads.

In general terms, the illustrated jack embodiment of the invention comprises a ram, cylinder, fluid reservoir and a pump adapted to force hydraulic fluid from the reservoir into the cylinder to actuate the ram therein. In use to lift a spring-supported load such as an automobile, the ram is placed in abutting engagement with the vehicle bumper or the like, and the pump is manipu lated to force hydraulic fluid into the cylinder so that the ram will move upwardly and lift the vehicle load. Only a portion of the total vehicle load is supported by the ram until the vehicle is lifted to a position whereat the spring suspension is fully extended and no longer supports any portion thereof. When the spring suspension has been fully extended by the upward movement of the ram, the next increments of upward movement lift the vehicle wheel or wheels from the ground. A plurality of energy storage chambers are mounted on the jack and contain a compressible fluid such as air. The energy storage chambers are connected to the ram cylinder by a fluid passage and an energy storage valve is disposed "ice in the passage. Energy transfer means in the form of hydraulic fluid from the ram cylinder fills the fluid passage and a portion of the energy storage chambers. The valve is normally closed, but may be manually opened when it is desired to permit energy to; be transferred to or from the energy storage means by the energy transfer means. When it is desired to return a lifted vehicle to engagement with the ground, the hydraulic fluid in the cylinder which supports the load is conventionally allowed to return to the reservoir under the force exerted by the weight of the load due to its elevated position. It is now proposed to open the energy stora'ge valve so that the weight of the load will force hydraulic fluid from the ram cylinder into the energy storagechambersand compress the air therein. The pressure of the air in the storage chambers willbe increased by compression until the force which it exerts on the ram through the hydraulic fluid is in equilibrium with the force exerted by the load. The energy storage valve is then closed to trap hydraulic fluid under pressure of the load in the energy storage chambers; and, if necessary, the jack is thereafter completely disengaged from the vehicle load by opening a manual release valve, which is disposed between theram cylinder and the reservoir, to permit the remaining hydraulic fluid in the ram cylinder to return to the reservoir in the conventional manner.

When it is desired to again use the jack to lift a load, the energy storage valve is manually opened. The compressed air in the energy storage chambers, forces the hydraulic fluid stored therein into the ram cylinder to partially lift the load to a point whereat the pressure exerted by the air in the energy storage chambers and the pressure exerted by the load on the fluid in the ram cylinder are again equalized. The load is conventional-' ly lifted the remainder of the way by the pump. Although the jack may be used in any type of application, it is particularly useful with spring-supported vehicle loads or the like whereat the jack must be initially extended a considerable distance during a lifting operation to move the vehicle load relative to the springs; and then, additionally extended some relatively shorter distance to obtain the desired clearance between the vehicle load and some fixed reference surface such as the ground. The length of overall travel of the load as it returns to its original position is directly proportional to. the energy which may be recovered and stored.

Referring now in detail to FIGURES 1 and 2, the jack is generally indicated at 10 and comprises a base 12 which may comprise a casting or similarly fabricated member adapted to support the various valves and other parts as described below. In the illustrated embodiment, base 12 is pivotally supported by trunnions 14, 16 which may form. part of a ground-engaging member and carry a pivot pin 18 passing through the lower end of the base. The upper end 20 ofthe base is adapted to support a ram cylinder 22 which is secured to and ex-.

tends upwardly therefrom. A piston or ram member 24 is slidably mounted within cylinder 22 and the outer end 26 thereof is adapted for connection directly to a load or to a load-engaging element shown partially in dotdash lines at 28 or other mechanism by means of which a load may be lifted when. the ram is moved upwardly. A reservoir housing 30 may be secured to base 12 and encloses a reservoir of hydraulic fluid 32 surrounding cylinder 22. Referring now to FIGURES 2 and 3, a pump means 34 is provided in the base 12 and comprises a cylindrical pumping chamber 36 within which a pumping rod 38 is slidably disposed. A handle 40 is pivotally secured at 42 to the outer end of the rod 38 and is pivotally supported at 44 to a bracket 46 attached to the base. Packing means 48,

are provided at the outer end of the pumping chamber and on the inner end of the rod. The fluid reservoir is connected to the pumping chamber by conduits 52, 54, 56. A filter 58 may be disposed in the reservoir at the entrance to conduit 52. A ball type check valve 60 is movably disposed .within conduit 54 and is urged against its seat by a spring 62. The valve 60 is located on the pump side of the valve seat so that outward movement of the pump rod 38 will cause the valve to be unseated and permit fluid to be drawn from reservoir 32 into chamber 36. An other ball type check valve 64 is disposed in a wider portion 65 of conduit 54. Valve 64 is urged against it seat by a spring 66 held in position by a plug 68. The valve seat is located on the reservoir side of conduit 54 so that the values 60, 64 will be oppositely actuated by the actuation of the pump. A conduit 68 leads from check valve 64 to a chamber 70 formed by ram 24 within cylinder 22. Consequently, when pump rod 38 is moved inwardly after having drawn fluid into chamber 36, fluid will flow through conduit 56 and conduit 54 past check valve 64 and throughconduit 68 into chamber 34 to extend ram 24 upwardly. The check valve 60 will be simultaneously closed.

As is best seen in FIGURE 2, a manually operable release valve 76 is threadably mounted in base 12 and movable by a handle portion 78 between open and closed positions. A conduit 30 leads from chamber 70 to one side of valve 76, and conduits 82, 84 lead from the other side of the valve back to reservoir chamber 32. When valve 76 is manually opened, fluid under pressure within chamber 70 can flow through conduits 80, 82, 84 back to the reservoir.

The illustrative novel energy-storing means comprises a pair of compression chambers 88, of tubular design which contain slidable piston elements 92, 94 and are mounted on opposite sides of base 12 by means of pairs of L-shaped fittings 96, 98 and 100, 102. Each of the chambers is closed at its outer end by plugs 104, 106 and is, adapted to contain a compressible fluid such as air above the pistons 92, 94. The chambers are hermetically sealed to prevent escape of the air when under compression and are mounted so as to extend upwardly in generally parallel relation with base 12 and reservoir housing 30. As many additional compression chambers may be provided as needed and the locations may be varied as desired. It is contemplated that the pistons might be eliminated in some applications where the compressible fluid in the chambers could be confined directly by the energy transmitting medium which acts thereon. In addition, spring means might be utilized as supplementary energy storing means or as substitute energy storing means.

A fluid passageway 108 leads from chamber 70 to a valve chamber 110 provided within base 12, as seen in FIGURE 2. A ball type energy storage valve 112 engages a seat 114 at one end of chamber 110 and is urged thereagainst by a relatively strong spring 115. As described below, spring 115 has suflicient force to prevent valve 112 from being lifted by the pressure exerted upon it from chambers 88, 90. The other side of seat 114 is connected to achamber 116 from which conduits 118, 120, 122 communicate with chambers 88, 90 through means of appropriate bores 124, 126 within the connecting fittings. A plunger 128 is slidably mounted in one end of chamber 116 and has an inwardly extending stem 130engageable with valve 112. A spring 132 is disposed within chamber 116 and urges plunger 128 in an outwardly direction, as seen in FIGURE 2, to a valve disengaging position. A handle 134 is pivotally mounted at 1 36 on base 12 and has a portion 138 engageable with a finger extension of plunger 128. When handle 134 is in itsnormal position shown in FIGURE 2, valve 112 is completely disengaged from the stem 130 and fully engages 'seat 114 under the urging of spring 115. However, when handle 134 is moved about pivot 136 toward 4 the base, the abutment surface 138 engages the finger 140 and moves the plunger 123 inwardly against valve 112. In this manner, the valve 112 may be moved oif the valve seat 114 against the bias of spring 115. g

In operation, assuming an initial condition in which jack 1% is collapsed or retracted and the chambers 88, 99 are in a non-energy stored condition, the release valve 76 is closed and pump rod 38 is reciprocated to extend the ram 24. When the pump rod 33 is moved outward, fluid is withdrawn from reservoir 32 and past check valve 60 and into pumping chamber 36 through passages 52, 54, 56. When the pump rod is moved inwardly, the valvetl is closed and fluid is driven from the pumping chamber through conduits 54, 56 and past valve 64 into the chamber 7 0 through conduit 68. The pump rod is reciprocated by actuation of the handle 40 until the end of the ram 26 has been moved a suflicient distance to displace the load as desired. During this time, valve 112 remains closed so that no hydraulic fluid will pass therethrough. When it is desired to lower the load and store energy in the jack for lifting the next load, handle 134 will be depressed to cause plunger stem 130 to lift valve 112 from its seat. The pressure exerted on the hydraulic fluid within chamber 70 by the load will cause the fluid to flow through passageway 108 past valve 112 and through chamber 116 to conduit 118. Fluid flows through conduits 121i, 124 to chamber 88 and through conduits 122, 126 to chamber 91) to exert a force on one side of pistons 92, 94. The pistons are upwardly displaced and compress the air which is trapped in the upper portions of the chambers. The pressure of air increases as the hydraulic fluid is forced into the chambers until it counterbalances the pressure exerted on the fluid within chamber 70 by the load and further downward movement of ram 24 is halted. The valve 112 is then closed by releasing handle 134 to trap fluid in the chambers 92, 94 and maintain the air in the compressed condition. Release valve 76 may then be opened by handle 78 and the hydraulic fluid remaining in chamber 70 will then be forced through passageway 80, past valve 76 and through passageways 32, 84 into reservoir 32 until ram 24 is moved to its fully retracted postion.

It should be noted that the spring 115 is designed to exert sufficient closing force on valve 112 to prevent any pressures exerted by the energy storage chambers from opening the valve. When it is again desired to use the jack, handle 134 will be depressed to open valve 112. The compressed air in chambers 88, 90 will expand and force the trapped hydraulic fluid from the lower portions of the chambers through conduits 120, 124 and 122, 126 to the chamber 116 through conduit 113. The fluid will flow past the valve 112 and into chamber 79 through conduit 108 to extend the ram until a load is encountered and moved a distance proportional to the energy stored in the chambers. FIGURES 4 and 5 are provided in order to illustrate the manner in which a jack embodying principles of this invention may aid in the lifting of spring-supported loads such as the bodies of automotive vehicles. The reference numeral 151) indicates a portion of a load such as an automotive vehicle supported by a plurality of wheels, one of which is indicated at 152, through the intermediary of springs 154. With such spring suspensions, the first small increment of upward movement of the load when the ram is first engaged therewith requires relatively little force, as indicated by the arrow 156 in FIGURE 4. As spring 154 is extended, the force required to lift load 150 increases, reaching its maximum when wheel 152 leaves the ground, as indicated by the arrow 158 in FIGURE 5. The load is usually lifted an additional distance after the wheel leaves the ground in order to raise wheel 152 a sufficient distance to enable a tire change or the like. The amount of potential energy created is directly proportional to the distance the load is moved.

When the jack is used to raise a spring-supported load, the first lifting of such a load may be accomplished entirely by actuation of the pump if the energy storage chambers 88, 90 are initially without pressure. After the load has been lifted to the position of FIGURE 5, with wheel 152 a substantial distance above the ground, the energy storage valve 112 may be opened to permit the load to descend with its full force building up a pressure in energy storage chambers until a force is developed therein which is equal and opposite to the portion of the load being supported when equilibrium conditions are attained. As described previously, the buildup of pressure will arrest the descent of the load, and the pressure may then be locked in chambers 88, 9t] by closing valve 112. The load is lowered the rest of the way by opening release valve 76. Upon the next lifting of load 150 from the position of FIGURE 4, valve 112 will be opened by handle 134. The compressed air under pressure in chambers 88, 90 will expand and move the pistons downwardly to move the trapped hydraulic fluid into the chamber 70 and extend the ram. The lifting movement will continue until the decreasing pressure in the chambers and the increasing resistance of load 150 come into balance. Valve 112 may then be closed, and the load lifted the rest of the way by reciprocation of pump rod 38.

It is thus seen that the novel jack of this invention will be of substantial assistance in raising spring-supported loads by lessening the manual effort required by the operator. It should be noted that the jack may also be of use in lifting loads which are not spring-supported, since in many cases the pressure stored in the storage chambers may provide useful assistance and reduce the total energy required to move the jack ram. The size and number of energy storage chambers may be so chosen as to be capable of moving any desired volume of hydraulic fluid for a given change in pressure of the compressible fluid. The relative volumes of the chambers and jack chamber 70 may thus be preselected to achieve a particular jack movement. It should also be observed that the operator will at all times havecomplete control of the jack, and will be able to stop the load in any desired position. Furthermore, other energy storing devices are contemplated in the broadest aspects of this invention. For example, the ram might be mechanically linked through a bell crank or the like to a spring element which would be compressed and store energy on the downward stroke of the ram. Latch means would be provided to maintain the spring in the compressed state until a subsequent upward stroke of the ram.

Although the preferred embodiment of the invention disclosed is particularly well adapted to accomplish the aforementioned objects and has advantages over other embodiments, the invention is susceptible to various modifications. Consequently, it is intended that the aforementioned modifications, and others, be included within the scope of the invention as defined by the appended claims except insofar as limited by the prior art.

What is claimed is:

1. In a lifting jack, a jack base, a cylinder mounted on said base, a ram slidably mounted in said cylinder and extending outwardly therefrom, said ram being movable between a lower and an upper position, a hydraulic fluid reservoir, a first fluid connection between said reservoir and said cylinder, pump means in said first fluid connection for forcing hydraulic fluid from said reservoir to said cylinder, a second fluid connection between said cylinder and said reservoir, a release valve in said second fluid connection for permitting hydraulic fluid to return from said cylinder to said reservoir, energy storage chamber means, a third fluid connection between said cylinder and said energy storage chamber means, means for retaining a compressible fluid in said energy storage chamber means in a manner such that hydraulic fluid forced into said chamber means will cause compression of said compressible fluid, and means for directing hydraulic fluid under pressure into said energy storage chamber means during downward movement of said ram from said upper position to said lower position to compress said compressible fluid and store energy developed during the downward movement of said ram.

2. In a vehicle lifting jack, a base, means for supporting said base on the ground so as to extend upwardly therefrom, a cylinder mounted on said base, a ram slidably mounted in said cylinder, a vehicle engaging member carried by the upper end of said ram, a hydraulic fluid reservoir, a first fluid connection between said reservoir and said cylinder, a pump connected to said first fluid connection for forcing hydraulic fluid from said reservoir to said cylinder to move said ram between a lower and an upper position, a second fluid connection between said cylinder and said reservoir, a release valve in said second fluid connection for permitting hydraulic fluid to return from said cylinder to said reservoir, energy storage chamber means, a third fluid connection between said cylinder and said energy storage means to transfer hydraulic fluid from said fluid reservoir to said energy storage chamber means, energy storage means mounted in said energy storage chamber means in a manner such that hydraulic fluid forced into said chamber means will increase the energy state of said energy storage means, and means for directing hydraulic fluid under pressure into said energy storage chamber means during downward movement of said ram from said upper position to the lower position to increase the energy state of said energy storage means.

3. In a lifting jack, a lifting member movable between a lower position and an upper position, manually operable means for moving said lifting member from the lower position to the upper position, means for releasing said lifting member from the upper position to allow a load supported thereby to force the lifting member to descend, energy storage means connected to said lifting member and being actuable between an energy released condition and an energy stored condition, said energy storage means being actuable from the energy released condition to the energy stored condition in response to descent of said lifting member under the load thereon, means for locking and maintaining said storage means in the energy stored condition caused by descent of said lifting member, re lease means connected to said lifting member and being movable between a non-releasing position and a releasing position permitting descent of said lifting member independently of said storage means, and means for releasing the energy in said storage means to assist subsequent -movement of said lifting member from the lower position to the upper position whereby said storage means is actuated from said energy stored condition to said energy released condition.

4. In a lifting jack, a jack base, a cylinder on said base, a ram slidable in said cylinder and adapted to be connected to a load to be lifted, a fluid reservoir, a first fluid connection between said reservoir and said cylinder, a pump in said fluid connection, means for manually actuating said pump to force hydraulic fluid from said reservoir into said cylinder to raise said ram, a second fluid connection between said cylinder and said reservoir, a release valve in said second fluid connection movable from a closed position holding fluid pumped to said cylinder therein to an open position permitting said hydraulic fluid to return from said cylinder to said reservoir to lower said ram, an energy storage chamber carried by said base and containing a compressible fluid, a hydraulic fluid connection between said cylinder and said energy storage chamber, and an energy storage valve in said last-mentioned hydraulic fluid connection, said energy storage valve being movable between an open position permitting a downwardly moving load on said ram to force hydraulic fluid from said cylinder into said energy storage chamber to compress said compressible fluid and a closed position maintaining said compressible fluid in a compressed state and store energy developed by downward movement of said load, and said energy storage valve being independent of said release valve whereby said ram may be raised and lowered independently of the energy storage means.

5. In a lifting jack, a jack base, a cylinder mounted on said base, a ram slidably mounted in said cylinder and extending outwardly therefrom, said ram being movable between a lower and an upper position, a hydraulic fluid reservoir, a first fluid connection between said reservoir and said cylinder, a manually operable pump in said first fluid connection for forcing hydraulic fluid from said reservoir to said cylinder, a second fluid connection between said cylinder and said reservoir, a manually operable release valve in said second fluid connection for permitting hydraulic fluid to return from said cylinder to said reservoir, elongated tubular energy storage chamber means mounted on said base and extending parallel to said cylinder, a third fluid connection between said cylinder and said energy storage chamber means, means for retaining a compressible fluid in said energy storage chamber means in a manner such that hydraulic fluid forced into said chamber means will cause compression of said compressible fluid, and means for directing hydraulic fluid under pressure into said energy storage chamber means during downward movement of said ram from said upper position to said lower position to compress said compressible fluid and store energy developed during the downward movement of said ram.

6. In a vehicle lifting jack, a base, means for supporting said base on the ground so as to extend upwardly therefrom, a cylinder mounted on said base and extending upwardly therefrom, a ram slidably mounted in said cylinder, a vehicle engaging member carried by the upper end of said ram, a reservoir housing surrounding said cylinder so as to form an annular reservoir chamber, a manually operable fluid pump adapted to force fluid from said reservoir into said cylinder to move said ram, upwardly in said cylinder, a fluid release connection between said cylinder and said reservoir, a manually operable release valve in said last-mentioned connection to hold fluid pumped to said cylinder in its unreleased condition and to permit fluid in said cylinder to return to said reservoir in its released condition, an elongated energy storage chamber mounted on said base and extending generally upwardly therefrom, said energy storage chamber being of tubular shape, means closing the outer end of said energy storage chamber, a piston slidably mounted in said chamber, a compressible fluid provided in said chamber between one side of said piston and the outer end of said chamber, a hydraulic fluid connection between said cylinder and said energy storage chamber on the other side of said piston, an energy storage control valve in said lastmentioned connection, and means for moving said energy storage control valve between an open position permitting hydraulic fluid to be forced from said cylinder into said energy storage chamber to compress said compressible fluid and a closed position locking said hydraulic fluid in said energy storage chamber and maintaining said compressible fluid in a compressed state.

7. In a vehicle lifting jack, a base, means for supporting said base on the ground so as to extend upwardly therefrom, a cylinder mounted on said base and extending upwardly therefrom, a ram slidably mounted in said cylinder, a vehicle engaging member carried by the upper end of said ram, a hydraulic fluid reservoir, a first fluid connection between said reservoir and said cylinder, a manually operable pump in said first fluid connection for forcing hydraulic fluid from said reservoir to said cylinder to move said ram between a lower and an upper position, a second fluid connection between said cylinder and said reservoir, a manually operable release valve in said second fluid connection for permitting hydraulic fluid to return from said cylinder to said reservoir, energy storage chamber means mounted on said base, a third fluid connection between said cylinder and said energy storage means to transfer hydraulic fluid from said fluid reservoir to said chamber means, energy storage means mounted in said energy storage chamber means in a manner such that hydraulic fluid forced into said chamber means will increase the energy state of said energy storage means, and means for directing hydraulic fluid under pressure into said energy storage chamber means during downward movement of said ram from said upper position to the lower position to increase the energy state of said energy storage means.

8. The invention as defined in claim 7 and wherein said last mentioned means comprises a valve means mounted in said third fluid connection and movable between open and closed positions therein, and valve control means mounted on said jack to actuate said valve means between said open and closed positions.

9. The invention as defined in claim 8 and wherein said valve means comprises a valve seat in said third fluid connection, a valve mounted on said valve seat for movement from a seated position thereon to an open position spaced therefrom, spring means biasing said valve to the seated position, said spring means being sufliciently strong to maintain said valve in the seated position throughout the range of energy storage capability of said energy storage means, said valve control means comprising movable stem means engageable with said valve to move said valve to the open position against the bias of said spring means, and manually operable actuating means connected to said stem means to selectively move said valve from the seated position to the open position.

References Cited by the Examiner UNITED STATES PATENTS 920,825 5/09 Clark 6052 1,619,474 3/27 Hubbard 6052 2,371,450 3/45 Langdon 6051 2,555,427 6/51 Trautman 6052 3,012,403 12/61 Wescott 6052 X 3,028,732 4/62 Shampaine et al 6052 X FOREIGN PATENTS 733,802 7/55 Great Britain.

JULIUS E. WEST, Primary Examiner.

EDGAR W. GEOGHEGAN, Examiner. 

1. IN A LIFTING JACK, A JACK BASE, A CYLINDER MOUNTED ON SAID BASE, A RAM SLIDABLY MOUNTED IN SAID CYLINDER AND EXTENDING OUTWARDLY THEREFROM, SAID RAM BEING MOVABLE BETWEEN A LOWER AND AN UPPER POSITION, A HYDRAULIC FLUID RESERVOIR, A FIRST FLUID CONNECTION BETWEEN SAID RESERVOIR AND SAID CYLINDER, PUMP MEANS IN SAID FIRST FLUID CONNECTION FOR FORCING HYDRAULIC FLUID FROM SAID RESERVOIR TO SAID CYLINDER, A SECOND FLUID CONNECTION BETWEEN SAID CYLINDER AND SAID RESERVOIR, A RELEASE VALVE IN SAID SECOND FLUID CONNECTION FOR PERMITTING HYDRUALIC FLUID TO RETURN FROM SAID CYLINDER TO SAID RESERVOIR, ENERGY STORAGE CHAMBER MEANS, A THIRD FLUID CONNECTION BETWEEN SAID 